Coastal Habitats Within Flood Risk Assessments: Role of the 2d SPR Approach

Abstract

Coastal habitats are highly threatened ecosystems that are sensitive to complex sets of natural and human drivers. Europe's coastal habitats are protected from damage due to human activity by the EU Habitats Directive, and are required to be mapped within flood risk assessments by the EU Floods Directive. Ecological vulnerability and risk assessments are a common way of assessing the impacts on these habitats due to human and natural drivers. Coastal flood risk assessments therefore often include assessments of the vulnerability of coastal habitats. Flood risk assessments also evaluate, where relevant, the mitigation services provided by coastal habitats. The two aspects of coastal habitats -their flood mitigation service and their ecological vulnerability are strongly correlated; however these are usually treated separately within flood risk assessments. One of the goals of the EU THESEUS project is the integrated consideration of coastal habitats within flood risk assessments. This paper investigates the integration within flood risk assessments of the two aspects of coastal habitats using the 2D SPR conceptual model. The construction of the model is first illustrated by application to a generic study site. The model is then applied to a casestudy where data on habitat elevations and vulnerabilities to flood events have been collected. The model provides a unique and robust means of combining information on ecological vulnerability indices for different habitat associations with information on their distribution and spatial relationships within the coastal floodplain. Used in conjunction with information on habitat vulnerability indices, the conceptual model serves as a powerful tool for integrated and structured consideration of coastal habitats within flood risk assessments.

Tall Wheatgrass (Thinopyrum ponticum): Flood Resilience, Growth Response to Sea Water Immersion, and Its Capacity for Erosion and Flooding Control of Coastal Areas

“…The main factor that affects and controls the viability, survival ability, and growth response of psammophytes is exposure time to sea water in naturally occurring flooding conditions or flood simulations [8]. The CDT for investigated species is 168 h, which is longer than floods with a maximum duration for the Bulgarian Black Sea Coast [15,29]. This value of the CDT is comparable with the results of psammophytes from the family Poaceae (A. arenaria and L. racemosus subsp.…”

“…The holistic approach of integrated coastal zone management recommends nature-based mitigation strategies based on the replacement of artificial coastal protection and stabilization structures with dunes stabilized with plants [12,14]. Natural dune vegetation reduces wind velocity, and with its extensive system of horizontal and vertical rhizomes, holds a large amounts of trapped sand that absorbs wave energy [9,[15][16][17]. Thereby, plants stabilize sand and act as supporters that increase the dunes' ability to reduce storm damages and effectively minimize erosion with minimal negative impacts to natural ecosystems [13,15,18].…”

“…Natural dune vegetation reduces wind velocity, and with its extensive system of horizontal and vertical rhizomes, holds a large amounts of trapped sand that absorbs wave energy [9,[15][16][17]. Thereby, plants stabilize sand and act as supporters that increase the dunes' ability to reduce storm damages and effectively minimize erosion with minimal negative impacts to natural ecosystems [13,15,18]. That is why searching for native salt-tolerant plant species with extensive root systems and investigating their capacity for flooding and erosion control is fundamental to the practice of ecologically sound ecosystem services [8,13,19].…”

Vulnerability assessment of coastal plant communities from flooding caused by unusual storms: A case study of Kabakum beach, Varna (Northeastern Bulgaria) for 2018 year

“…The main reasons for this are the small amplitude tides in the Black Sea and the lack of big rivers flowing into the Varna Bay [7,8,9]. The only risk comes from extreme meteorological events such as unusual storm surge levels in combination with reinforced wave upon the shore [7,10,11]. Recorded damages from storms over the Bulgarian Black Sea Coast [7,8,9] showed the negative impact to the dunes and the high potential of the root systems of some of the native psammophytes to accumulate sand and prevent from washout [3,[9][10][11].…”

“…The necessity to assess and to quantify these negative effects on natural habitats requires the development of rapid models for vulnerability assessment. Different flood scenarios and models were introduced in order to assess possible negative consequences to coastal areas from storms [7,10,11]. However, more of them are focused only to socioeconomic dimensions [e. g. 14].…”